1. Field of the Invention
The present invention relates to an exchange-spring magnet, and a method for manufacturing thereof. More specifically, the invention relates to an exchange-spring magnet having excellent magnetic properties, and a method for manufacturing thereof.
2. Description of the Related Art
An exchange-spring magnet containing a mixture of permanent magnetic phase (hard phase) and a soft magnetic phase (soft phase) in nano-size is currently attracting attention as a novel magnet material. As the exchange-spring magnet contains the soft phase of a high magnetic flux density, a magnetic flux density of the entire magnet is increased. Thus, a dramatic improvement of magnetic properties is enabled. The development of the exchange-spring magnet has been pursued in connection with a composition system where the hard phase contains Neodymium-Iron-Boron, and the soft phase contains Iron or Iron-Boron.
A real exchange-spring magnet shows high magnetic properties in the amount of the rare earth element set within a range of 8 to 9 atom %. However, micromagnetics simulation provides a possibility of further improvement of the magnetic properties by forming a low rare earth element composition, i.e., a composition of a large soft phase content. This is attributed to the fact that since the soft phase has a high magnetic flux density as described above, the magnetic flux density of the entire magnet is set higher by increasing the soft phase content.